I met this woman who'd dated my ex. In talking, we realized that he used the same romantic lines on both of us. Granted, these made me feel good at the time, but I feel angry and stupid for falling for them. How do you know when a guy is sincere?

--Scammed

Understandably, you want a man's lovey-dovey talk to come from the heart, not from a Word doc he saved on his hard drive.

However, a guy whose heartfelt remarks turn out to be a renewable resource isn't necessarily some sneaky recycler. Consider how personality plays into this. Personality is a pattern over time of thoughts, feelings, and desires that shape how you behave. Research by social psychologist Nathan W. Hudson suggests that you may be able to change aspects of your personality through behavioral change -- like by repeatedly acting more conscientiously. Still, Hudson -- along with about 10 truckloads of other social psychologists -- sees a good deal of evidence that personality is "relatively stable."

In other words, even a sweet, sincere guy is likely to use some of the same romantic wordery with any woman he's dating. What tells you whether he's a good guy or he just talks a good game is time -- reserving judgment on what you have together until enough time passes for you to hold up the sweet things he says to what he actually does. Wanting to see any discrepancies is really the best way to protect yourself from serial romancers -- or worse. ("I bet you say that to all the girls you put in your freezer!")